生产环境高并发MySQLSQL语句优化案例

生产环境高并发MySQLSQL语句优化10条案例声明：本案例为老男孩linux运维实战培训的数据库优化教学案例，如有转载务必保留本版权声明在实际工作中，运维或DBA人员

?,'?,'?,'绉︽矝','寰愬厠');

最终解决方案：有用到boy_title_upper的索引，慢的原因再观察

案例4：分析归类后的慢查询日志如下。

______________________________________________________________________ 004 ___

Count: 378(6.04%)

Time: 2604 s total, 6.888889 s avg, 3 s to 65 s max(7.63%)

95% of Time : 2031 s total, 5.657382 s avg, 3 s to 17 s max

Lock Time (s) : 0 total, 0 avg, 0 to 0 max(0.00%)

95% of Lock : 0 total, 0 avg, 0 to 0 max

Rows sent: 5 avg, 0 to 10 max(3.24%)

Rows examined : 2.81k avg, 92 to 24.91k max(27.61%)

Database: docresource

Users:

ett_oldboy@ 10.0.1.28 : 100.00% (378) of query, 100.00% (6256) of all users

Query abstract:

SELECT h.boy_id ,MAX(h.boy_his_edit_time) AS boy_his_edit_time FROM t_boy_his h WHERE h.boy_his_isteammate=N AND h.boy_his_state=N AND h.boy_his_editor_user_id_encrypt='S' GROUP BY h.boy_id ORDER BY h.boy_his_edit_time DESC LIMIT N,N;

Query sample:

selecth.boy_id ,max(h.boy_his_edit_time) from t_boy_his hwhere h.boy_his_editor_user_id_encrypt='pGVpWQVlYdglTaQ0Z' and h.boy_his_isteammate=1 and h.boy_his_state=1 group by h.boy_id order by h.boy_his_edit_time desc limit 0,4;

最终解决方案：

alter table t_boy_his add index editor_user_iden_docid(boy_his_editor_user_id_encrypt, boy_id);

1,sql改成：SELECT h.boy_id ,MAX(h.boy_his_edit_time) AS boy_his_edit_time FROM t_boy_his h WHERE h.boy_his_isteammate='pGVpWQVlYdglTaQ0Z' AND h.boy_his_state=1 AND h.boy_his_editor_user_id_encrypt='S' GROUP BY h.boy_id ORDER BY null

2，再在程序里，用java对boy_his_edit_time排序。

案例5：分析归类后的慢查询日志如下。

______________________________________________________________________ 005 ___

Count: 211(3.37%)

Time: 1218 s total, 5.772512 s avg, 3 s to 30 s max(3.57%)

95% of Time : 1022 s total, 5.11 s avg, 3 s to 13 s max

Lock Time (s) : 0 total, 0 avg, 0 to 0 max(0.00%)

95% of Lock : 0 total, 0 avg, 0 to 0 max

Rows sent: 2 avg, 0 to 2 max(0.72%)

Rows examined : 3.61k avg, 110 to 19.59k max(19.81%)

Database:

Users:

ett_oldboy@ 10.0.1.28 : 100.00% (211) of query, 100.00% (6256) of all users

Query abstract:

SELECT h.boy_id ,MAX(h.boy_his_edit_time) AS boy_his_edit_time FROM t_boy_his h WHERE h.boy_his_isteammate=N AND h.boy_his_state=N AND h.boy_his_editor_user_id=N GROUP BY h.boy_id ORDER BY h.boy_his_edit_time DESC LIMIT N,N;

Query sample:

selecth.boy_id ,max(h.boy_his_edit_time) as boy_his_edit_time from t_boy_his hwhere h.boy_his_isteammate=1 and h.boy_his_state=1 and h.boy_his_editor_user_id=300000178518 group by h.boy_id order by h.boy_his_edit_time desc limit 0,2;

最终解决方案：此sql由查前面一个sql代替，删除。

案例6：分析归类后的慢查询日志如下。

______________________________________________________________________ 006 ___

Count: 30(0.48%)

Time: 940 s total, 31.333333 s avg, 3 s to 77 s max(2.76%)

95% of Time : 790 s total, 28.214286 s avg, 3 s to 69 s max

Lock Time (s) : 0 total, 0 avg, 0 to 0 max(0.00%)

95% of Lock : 0 total, 0 avg, 0 to 0 max

Rows sent: 1 avg, 1 to 1 max(0.05%)

Rows examined : 10.96k avg, 1.82k to 28.12k max(8.56%)

Database: docresource

Users:

ett_oldboy@ 10.0.1.28 : 100.00% (30) of query, 100.00% (6256) of all users

Query abstract: